1. Field of the Invention
This invention relates to diagnostic method and apparatus based upon a polymorphism in a vitamin D receptor gene. More specifically, this invention relates to a method for diagnosis of pre-disposition or susceptibility to certain disease states, by screening for the presence of this polymorphism. The invention also relates to compositions for screening for the polymorphism.
2. Related Art
Osteoarthritis, or degenerative joint disease as it is also known, is one of the most common types of arthritis. It is characterised by the breakdown of the joint's cartilage, causing bone to rub against bone causing pain and loss of movement. Osteoarthritis can range from very mild to very severe and most commonly affects middle-aged and older people. It affects hands and weight-bearing joints, such as the knees, hips, feet and back.
Although age is a leading risk factor, at present the aetiology and pathogenesis of this condition remain largely unknown. Many environmental factors and other independent conditions have been associated with osteoarthritis, including obesity, previous injury and/or menisectomy, knee bending occupations, smoking, sex hormones, gynaecological disorders and other metabolic factors. Obesity may lead to osteoarthritis of the knees. Also, people with injuries to the joints because of sports, repeated movements, or accidents may be at increased risk of developing osteoarthritis.
At present accurate diagnosis of osteoarthritis is in general possible only when the disease has progressed significantly. Physicians can do little more than make a diagnosis of osteoarthritis based on a physical examination and history of symptoms. X-ray is typically used only to confirm diagnosis.
A recent study concluded that weight loss in middle-aged people who are overweight can significantly reduce the risk or even prevent knee osteoarthritis from developing. In such cases an ability to improve accuracy of diagnosis of predisposition or susceptibility to osteoarthritis would be of distinct advantage.